Before I visited, the extent of the knowledge that I had was that Australia, in fact, was a British Penal Colony a long time ago.

The reason that Australia became a part of the British Penal system was simple; Britain wanted to colonize. The French and Japanese had their eye on the land what is now Australia. Since England was overcrowded as it was, this was a good move to get the really bad prisoners away from the mainland. This is about the farthest away they could have gotten, and could solidify their position in the territory.